Buildability

The Legislation

To reduce the number of workers on site and to achieve higher site productivity, the industry has to adopt more labour efficient designs and use of pre-assembled products.
A key measure to achieve this is the introduction of regulations under the Building Control Act, which require building designs to have a minimum buildable design score.

The Building Control Act was amended to facilitate the introduction of new regulations for improving the efficiency and standardisation in designs, processes, construction techniques, products and materials.
The regulations pertaining to buildable design was first gazetted on 12 December 2000 and the legislation of buildable design was implemented on 1 January 2001.
Projects submitted for URA planning permission on or after 1 January 2001 will be affected by the legislation and are required to comply with a minimum Buildable Design Score.

The Buildable Design Score (B-Score) measures the potential impact of a building design on labour usage. It facilitates the adoption of less labour intensive construction methods and promotes greater
use of prefabricated, modular and standardised building components. A design with a higher B-score will result in more efficient labour usage in construction and hence higher site labour productivity.

To accelerate the pace of buildable design adoption, BCA has over the years since 2001, raised the minimum B-Score standard. Depending on the date of planning submission, a project with
Gross Floor Area (GFA) of 2,000 m2 and above would be subjected to the minimum B-Score requirement as set out in the relevant Code of Practice on Buildable Design/Buildability as shown in Table 1 below.

In addition to requiring designers to deliver more buildable designs upstream, builders must also play their part to adopt more labour-saving construction methods/technologies downstream. As such, with effect from
15 July 2011, builders of building projects with GFA of 5,000 m2 and above have to comply with a minimum Constructability Score (C-Score) which encourages the use of construction technologies, methods and processes to reduce the
industry's reliance on foreign workers. The C-Score measures the level of adoption of labour-efficient construction methods and construction processes such as system formwork and climbable scaffolding. Higher C-Scores would translate
to savings in manpower cost and shorter construction time.

Similar to B-Scores, over the years since its introduction, the minimum C-Score requirements have also been raised. These requirements are set out in the relevant Code of Practice on Buildability as shown in Table 1.

Besides the minimum buildability standards, the Code of Practice on Buildability (COP) also covers the legislative requirements, submission procedures and method for computing the B-Score and C-Score.

Enhanced Buildability Framework from 1 May 2017

In December 2015, BCA raised the minimum buildability standards and introduced the mandatory adoption of productive technologies
such as welded mesh for cast in-situ concrete floor and prefabricated and pre-insulated duct for air-conditioning systems for all developments. As part of the larger drive towards wider adoption of prefabrication technologies
along the Design for Manufacturing and Assembly (DfMA) continuum, there is a need to further enhance the buildability legislative framework to raise construction productivity. BCA has hence amended the Building Control (Buildability and Productivity) Regulations.

Under the enhanced buildability framework, the changes are:

(A) Higher minimum level of use of prefabrication systems for developments on sites sold under the Industrial Government Land Sales (IGLS) Programme